How to find Battery Voltage

[jeepgrady]

Uh, interesting. I have a lariat also, and it couldn't be easier to hold down OK while pushing the start button. It works.

Voltage running. (It looks weird because it's bouncing between 14.7 and 14.8V)

Voltage off.

If you're investigating deep sleep, trying to prove a weak battery, etc I personally would not want to mess with that compared to just using a device that is plugged in to always show voltage. That's why I replied as such the first time, and I assumed the other reply about ET works. But since my truck is just outside my office door I went and tried it.

Plus it functions just like your Corsair, LOL.

Ok. Got it to work. Vehicle on 15.1 volts. Off 14 volts. Aren't those readings a bit odd as I just used the truck day before yesterday on a 2 hour drive.

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[colinl]

Ok. Got it to work. Vehicle on 15.1 volts. Off 14 volts. Aren't those readings a bit odd as I just used the truck day before yesterday on a 2 hour drive.

I would bet money you have an AGM battery, that's much of the difference in your readings and mine, because mine is EF. Or is there something else you find odd?

 

[jeepgrady]

Ok. Got it to work. Vehicle on 15.1 volts. Off 14 volts. Aren't those readings a bit odd as I just used the truck day before yesterday on a 2 hour drive.

Let me correct my first reading. When engine is off it reads 12 volts. Isn't that a bit low, and isn't 15.1 while running high? Yes it is AGM.

 

[colinl]

Let me correct my first reading. When engine is off it reads 12 volts. Isn't that a bit low, and isn't 15.1 while running high? Yes it is AGM.

the reason why I guessed you had AGM is because my Bronco has one and it routinely shows 15.1-15.2 V running, but my Maverick never goes above 14.8. AGM operates at a slightly higher voltage and is way more tolerant of 50% discharge state than a flooded battery. neither battery type likes being discharged below 50, but the AGM loses less capacity down to like 25% than flooded. below 25% both are permanently losing capacity (and will eventually fail).

by 12v if you meant 12.0 yes that is pretty low in general and especially AGM. I would want to see 12.4 or higher with AGM. can reset the Battery Monitoring System, it's very easy. it's required when changing the battery, and it can help with existing batteries that are showing low charge when the ignition is off. a year ago my truck was going into deep sleep all the time. I reset the BMS and nothing for a year, but full disclosure, I did get one a week ago and it hasn't happened since.




Resetting the Battery Sensor


When you install a new battery, reset the battery sensor by doing the following:

1. Switch the ignition on, and leave the engine off.

Note: Complete Steps 2 and 3 within 10 seconds.

1. Flash the high beam headlamps five times, ending with the high beams off.

1. Press and release the brake pedal three times.

The battery warning lamp flashes three times to confirm that the reset is successful.

 

[jeepgrady]

Thanks for your thorough explanation. I previously reset the sensor. It just appears that the battery discharges too quickly, ie, 12 volts resting after a 2 hour drive day before yesterday. Not to mention getting the ubiquitous low battery message. I'll keep an eye on it

 

[colinl]

That sounds like your battery is on its way out, unfortunately. A good Ford dealership should take care of it for you once it reaches the state of going into deep sleep every time you shut off the ignition, but if you search here, you can find plenty of people whose dealerships fail to do that.

 

[Rlward]

OBD Reader and Torque app should show it? But I haven't looked.

Yes the obd apps will display the 12 volt battery stats. Be nice if they would display the hybrid battery level too.

 

[MetalsGeek]

I'm trying to determine the voltage my battery is putting out without attaching a meter. I know in my 22 Corsair you can enter "Engineering Mode", by pressing a specific button on the steering wheel while starting the engine. The mode displays all sorts of info, including the battery Voltage. Anyone have an idea how to do this on the Maverick?

I have a 23 XLT hybrid. Hold down OK button AND step on brake pedal for 5 sec. Insert key and turn past ACCY to ON, but not to Start. Within 15 seconds you should see green ET on screen; release OK & brake. Use menu buttons to navigate. Can't recall what it shows.

 

[semicolin]

Does the battery voltage rail fluctuate in a hybrid when the engine turns off?

Eg: when the engine is running it charges the 12V battery like a traditional alternator would around 15V, and then when the engine cuts out it drops to 12V? Or does the hybrid keep it high as long as the key is in the on position?

 

[Master Blaster]

You need to measure the battery voltage at the battery on a Hybrid while off for at least a few hours.
When you put the truck into Engineering Test mode then the HV battery is charging the 12V battery even though the vehicle is in accessory mode and does not need to be running. The ET display will show something over 15V, which is what it gives while the 12V battery is charging.
If you leave the vehicle overnight to bleed off the surface charge, a new 12V battery should read 12.4V-12.6V. If it reads less than 12.2V then it is having issues. If it reads under 12.0V then you should be seeing the dreaded deep sleep messages, as it is not retaining more than a 20% charge and is probably heavily sulphated.

 

[Darnon]

You will get some voltage rise in the accessory position, but I think that's just the DC/DC converter utilizing some HV from the precharge capacitor. Not sure how much amperage the DC/DC converter is actually putting out in that state.

 

[semicolin]

The reason why I'm asking is because I'm about to install a radio transceiver with a PowerWerx ITS-12 Automatic DC timer/LV disconnect.

When the input voltage is 13.0-14.5V, the contacts close and provide power on the output terminals. When the input voltage is 12.6V or less, a timer starts a countdown to open the contacts and shut down power on the output terminals.

On a normal vehicle, these voltage correspond with the ICE running an alternator. I want to know if the voltage provided to the battery will drop below 12.6V and start the timer every time the engine stops, or if the voltage will only drop below 12.6V when I take the key out of run mode, like it would on a normal vehicle.

 

[Darnon]

I want to know if the voltage provided to the battery will drop below 12.6V and start the timer every time the engine stops,

No.

or if the voltage will only drop below 12.6V when I take the key out of run mode, like it would on a normal vehicle.

Yes, mostly. See caveat about accessory position.

 

[semicolin]

Perfect. It's worth spending the money on the ITS-12 since it will probably work properly and I don't feel like killing my battery because I forgot the rig turned on.

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